6.1 Flashcards
How long does it take for rigor mortis to fully come into effect?
6-8 hours
Why does rigor mortis occur?
ATP is required to keep the muscles relaxed, after death this runs out leading to contraction
What factor determines how long it takes for rigor mortis to come into effect?
The level of ATP in the muscles at time of death
Where does rigor mortis start?
In the face and neck and progresses slowly down the body
How long does it take for rigor mortis to pass?
Between 36 and 48 hours after death
How many stages are there in succession?
Four
What does the first stage of bodily succession involve?
Colonisers such as anaerobic bacteria
What does the second stage of bodily succession involve?
Species of flies and their maggots
What does the third stage of bodily succession involve?
Species of beetles in which parasitic wasps lay their eggs
What is the fourth stage of succession?
Species of mites and moth larvae which feed on hair
What four factors effect the speed of decay?
Temperature of body and surroundings
Level of exposure
Whether the body is burned
Whether the body is suspended in water
What is the study of insects that colonise a body after death known as?
Forensic entomology
What type of code is DNA?
A triplet code
What does degenerate mean?
There are many different instances in which different codons specify for the same amino acid ( there is more than enough code for what is needed )
What does over 90% of DNA consist of?
Introns
What are introns?
Non coding regions of DNA that are spliced out
What are the repeating patterns on base pairs called within introns?
Mini and micro satellites
How long are mini satellites?
20-50 base pairs
How long are micro satellites?
2-4 base pairs
Where are satellites found?
On the same positions on each pair of homologous chromosomes
How are DNA profiles produced?
Using a process called gel electro phoresis
What enzymes chop up strands of DNA into fragments in gel electrophoresis?
Restriction endonucleases
Where is the DNA cut in gel electrophoresis?
At specific sites know as recognition sites
In gel electrophoresis, where are the fragments of DNA placed?
In wells of agarose gel medium in a buffering solution
What is the dyes function in gel electrophoresis?
To make the DNA fragments glow under ultraviolet light
In which direction does the DNA move in gel electrophoresis?
Towards to positive anode
How many stages are there in the PCR l?
Three
What is the temperature of the first stage of the PCR and how long does it last?
90-95 degrees for 30 seconds
What occurs in the first stage of the PCR?
The DNA strands separate
What temp is the second stage of the PCR and how long does it last for?
50-60 degrees for 20 seconds
What occurs in the second stage of the PCR?
Primers bind to the DNA strands
What temperature and for how long is the third stage of the PCR?
75 degrees for 60 seconds
What occurs in the third stage of the PCR?
DNA polymerase builds up a complementary stand of DNA from the primers
How long does it take for rigor mortis to set in after death?
2-4 hours
